1. Field of the Invention
The present invention relates to a method of producing a multicolor pixel sheet and a color filter using the same, and in particular, to a color filter with a black matrix that has a light-shielding film with high optical density and serves as a spacer, and a method of simply and accurately producing a multicolor pixel sheet suited for producing the color filter.
2. Description of the Related Art
In a conventional liquid crystal display, two substrates, i.e., a color filter substrate and a counter electrode substrate, are laminated with spacer beads, such as plastic beads and ceramic beads having a predetermined diameter, dispersed therebetween to keep the thickness of a liquid crystal layer (cell gap) constant. However, because it is difficult to disperse the spacer beads regularly, the cell gap cannot be kept completely constant over the display area. When the number of the spacer beads is increased, the cell gap can be constant, but aperture ratio of the display area is undesirably lowered because of the spacers disposed at the display area. Further, the spacer beads may damage an orientation film or transparent electrodes when the two substrates are laminated together, and may thereby cause display defects.
To solve this problem, Japanese Patent Application Laid-Open (JP-A) No. 5-196946 discloses spacers formed by stacking two or three coloring layers of a color filter substrate. In these applications, each coloring layer must have sufficient and precise thickness to form spacers which have a height corresponding to the desired cell gap. JP-A No. 2000-314804 discloses a method of producing a black matrix and spacers by exposing the substrate from both the upper and lower surfaces of the substrate. This method utilizes a conventional development method using a conventional photosensitive black resin. However, the optical density of the obtained black matrix is 2.5 at most, which is below the required optical density of 3.5 or more. JP-A No. 11-14823 discloses a method of producing a black matrix having high optical density by exposing the substrate only from the lower surface thereof. In this method, although a black matrix with high optical density may be obtained, the thickness of the obtained black matrix is the same as those of the spacers, which may cause an undesirable liquid crystal domain and make it difficult to inject liquid crystal.